Measurement Techniques in Animal Locomotion Analysis

Abstract

Animal performance can be determined by subjective observations or objective measurements. Numerical data are only then superior to results of subjective observations when they are the result of measurements carried out to test a well-defined hypothesis or to give the answer to a clear, precisely formulated question. In the analysis of kinematics a careful evaluation of the set-up of the measurement equipment and the resulting accuracy in the data is required. Measurements in three dimensions (3D) are theoretically better than those in 2D. Practically, however, collection, analysis, interpretation and presentation of 3D data are so much more complicated that frequently 2D analysis appears to be more useful. The minimal size of markers necessary to obtain a certain accuracy in kinematic data is usually too big for practical use. Smaller markers impair accuracy. Reduction of measurement noise is obligatory when time derivatives are to be calculated. Skin movement artefacts cannot be removed by data smoothing. Forces occurring between the digits and the ground can be determined using a force plate or an instrumented shoe. A force plate is accurate, but repeated trials are necessary. Using a force shoe each ground contact results in useful data. However, the shoe itself may affect locomotion. Surface strains on long bones can be recorded relatively easily. Determination of loading forces from surface strains is complicated but can be carried out using multiple strain gauges and a post-mortem calibration test. Strain in tendons is difficult to measure due to problems in defining a ‘zero’ or reference length. Tendon forces can either be calculated from signals of parallel, compliant transducers or estimated by application of tendon buckles or wedge-shaped implantable transducers. In both cases a calibration procedure is required to convert transducer signals to tendon forces.

Lateral sequence walking in infant Papio cynocephalus: Implications for the evolution of diagonal sequence walking in primates

“…Hindlimb angle was calculated as the angle formed between a line connecting the hip and ankle markers relative to a vertical line through the hip marker. Hip and ankle marker locations exhibit minimal skin movement (see also Goslow et al, 1973) and are therefore reliable areas for kinematic study (Schamhardt et al, 1993). Positive angles indicate that the hip-ankle segment is protracted relative to the vertical, and negative angles indicate retraction of the hip-ankle segment (Fig.…”

Gait assessment in dairy cattle

“…One alternative is to use force-recording shoes that avoid the issue of foot placement on the force plate. Researchers have developed force-recording shoes for horses (Schamhardt et al, 1993;Barrey, 1999), but these are heavier and thicker than regular horseshoes and thus may shorten strides and swing phases and increase the effort needed to move the limbs (Roepstorff and Drevemo, 1993).…”

“…For example, Van Weeren et al (1988) quantified marker position errors in horses and reported displacements of <2 mm at the fetlock joint but up to 20 mm at the distal end of the tibia. Schamhardt et al (1993) suggested using sites where skin movement is Flower and Weary negligible, at the fetlock for example, but this approach might not detect problems higher up the limb, such as arthritis in the hip joint.…”

Biomechanics of locomotion in the athletic horse

“…4,5 They are intended to indicate the approximate instantaneous center of rotation of the joint. 6,7 However, the skin displacements over the skeleton during locomotion generate some artifacts, especially in the proximal joints. 8,9 The processing of the fi lm for collecting the joint marker coordinates is undertaken using a computer.…”